This brief presents the concept of “natural” cultural district as a vehicle to translate grassroots culture into urban revitalization. The term is both descriptive and analytical. Descriptively, a “natural” cultural district identifies a neighborhood that has spawned a density of assets—organizations, businesses, participants, and artists—that sets it apart from other neighborhoods. Analytically, cultural clusters are of interest because of density’s side effects. They can build community, spur cultural production, and attract new services and residents. The challenge is how to encourage these geographically-defined social networks without snuffing out the spark that makes them distinctive. “Natural” cultural districts must be cultivated. To do so, we mush first understand their ecology and how they fit into the contemporary urban arts scene.